Formulation development and characterization of lamotrigine-salicylic acid crystalline product: A strategy to improve oral release of drug for better management of epilepsy

Abstract

Lamotrigine, a FDA approved antiepileptic drug is widely used in the treatment of epilepsy and bipolar disorder. However, poor aqueous solubility and low dissolution rate limit its oral absorption leading to a delayed onset of action with reduced therapeutic effect. The present study aims for the development of formulation and characterization of lamotrigine-salicylic acid crystalline product for the improvement of oral release and absorption for better management of epilepsy. The crystalline product of LT are developed with SA at 1:1, 2:1, 3:1 molar ratios by solvent evaporation method. The experimental crystals have been characterized by different analytical techniques such as fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD) etc. Presence of characteristic peaks for peptide in the experimental crystalline products in FTIR spectra indicates formation of strong covalent bond between LA and SA. In the DSC thermograms, melting endotherm of the formulations showed different melting points than pure LT. PXRD data depicted sharp peaks for the formulations, which further justified the successful formation of a new crystalline phase. Dissolution profile of the experimental crystal (L1S1 at 1:1 molar ratio) in simulated gastric fluid was higher than that of the pure drug and other formulations. The optimized crystalline product of LT may be used for the better oral treatment of epilepsy with early onset of action after successful in vivo studies.